Autonomous in Situ Analysis and Real-Time Chemical Detection Using a Backpack Miniature Mass Spectrometer: Concept, Instrumentation Development, and Performance

Abstract

A major design objective of portable mass spectrometers is the ability to perform in situ chemical analysis on target samples in their native states in the undisturbed environment. The miniature instrument described here is fully contained in a wearable backpack (10 kg) with a geometry-independent low-temperature plasma (LTP) ion source integrated into a hand-held head unit (2 kg) to allow direct surface sampling and analysis. Detection of chemical warfare agent (CWA) simulants, illicit drugs, and explosives is demonstrated at nanogram levels directly from surfaces in near real time including those that have complex geometries, those that are heat-sensitive, and those bearing complex sample matrices. The instrument consumes an average of 65 W of power and can be operated autonomously under battery power for ca. 1.5 h, including the initial pump-down of the manifold. The maximum mass-to-charge ratio is 925 Th with mass resolution of 1-2 amu full width at half-maximun (fwhm) across the mass range. Multiple stages of tandem analysis can be performed to identify individual compounds in complex mixtures. Both positive and negative ion modes are available. A graphical user interface (GUI) is available for novice users to facilitate data acquisition and real-time spectral matching.

Direct drug analysis from oral fluid using medical swab touch spray mass spectrometry

“…Schwab et al [17] recently stated that “… a series of revolutionary developments in MS is turning this complex technique into a model of simplicity …,” a vision of MS utilization which the authors share. Prospectively, the adoption of transportable mass spectrometers [18,19] and ambient ionization techniques – which allow the generation of ions under atmospheric conditions and require minimal to no sample preparation [20] – holds the potential for the development of in situ , rapid and straightforward analysis of intact oral fluid without significantly compromising the selectivity, sensitivity, and wide applicability that MS offers [17]. …”

Design of Portable Mass Spectrometers with Handheld Probes: Aspects of the Sampling and Miniature Pumping Systems

“…and 0.5mm i.d. To operate the coaxial LTP probe,[13] an ac voltage of 1,000V at 30kHz was used to induce a helium discharge (flow rate 0.2L/min). 2,4-Dinitrophenol (DNP) dissolved in pure methanol solution was used with nanoESI for these test analyses.…”

“…These types of applications can benefit from the miniaturization of the MS analytical systems, a topic which has been actively pursued using the combination of miniature mass spectrometers and ambient ionization sources. [10-13] Different types of mass spectrometers have been miniaturized, including time-of-flight,[14-16] quadrupole,[17, 18] and ion trap systems. [19-24] The advantages of ion trap analyzers include their small size, relatively high operating pressure and the MS/MS capability.…”

“…A backpack MS system has recently been developed using this configuration with a coaxial LTP. [13] In this as in all experiments using miniature mass spectrometer, use of the discontinuous atmospheric pressure interface (DAPI)[46] for ion introduction is essential.…”

Mini 2000: A Robust Miniature Mass Spectrometer with Continuous Atmospheric Pressure Interface

“…Up until now, different kinds of miniature mass spectrometers have been developed, mainly using an ion trap as the mass analyzer, which is connected with different atmospheric pressure interfaces (APIs), including the membrane inlet (MI) [14][15][16][17], discontinuous atmospheric pressure interface (DAPI) [10,18,19], and continuous atmospheric pressure interface (CAPI) [20,21]. Among these APIs, MI was the first one to be adopted in MS systems.…”